It is customary at present to place test tubes in an upright position in a rectangular rack, and after adding samples and/or reagents into the test tubes, to manually transfer each test tube separately into cells of a circular centrifuge at an angle. As a result, there is a problem of time wasted in transferring the test tubes one by one into the centrifuge. There are many kinds of centrifuges; the most common ones contain either 24 or 36 cells for test tubes. It is important to point out that the centrifuge cells are set at an angle and, therefore, the test tubes are required to be inserted therein a at about a 45-degree angle. The use of Eppendorf centrifuge test tubes and suitable centrifuges are very common in research laboratories and medical institutions worldwide.
The Eppendorf centrifuge tube has become a generic trademark for microfuge tubes or microcentrifuge tubes. They are small, cylindrical plastic containers with conical bottoms, typically with an integral snapcap, disposable and inexpensive. They are used in molecular biology and biochemistry to store and centrifuge small amounts of liquid. They are used by many chemists and biologists as convenient sample vials in lieu of glass vials and are particularly useful when there is only a small amount of liquid sample or when small amounts of reagents are to be added, because microcentrifugation can be used to collect the drops at the bottom of the tube after pipetting or mixing. Eppendorf is a major manufacturer of test tubes of this type, but it is not the only one. A typical table-top laboratory centrifuge today is provided with a circular rotor (see, for example, the Ohne FC&W model EBA 12R centrifuge). The rotor is conical providing a 45-degree slope for the cells into which the test tubes containing samples are to be inserted for centrifuging.
As mentioned earlier, one problem with such a centrifuge method is that much time is needed to place each test tube individually into the cells of the rotor. Furthermore, the current method of using a rectangular test tube racks makes it impossible to place the test tubes directly from the rack into a conical, i.e., circular, rotor of a centrifuge.
The present invention comes to solve this problem by providing a flexible, test tube holder ring which, when placed lying flat on a corresponding round rack, can accommodate a number of test tubes inserted vertically, and when these are to be transferred to a centrifuge by means of the holder ring, the test tubes are pivoted at an angle to match the angle of the conical centrifuge cells due to the change in shape of the flexible, flat holder ring. Moreover, when retrieving the test tubes from the centrifuge, the flexible holder ring is able to adjust its angle to accommodate the angle of the test tubes as these are removed from the angular centrifuge cells.
The prior art that relates to the field of the present invention includes: U.S. Pat. No. 3,361,343; U.S. Pat. No. 3,713,771; U.S.2006/0198759, U.S.2010/0031760 A1; U.S.2010/0314344 A1 and DE 3217625 A1. All these patents provide racks for receiving test tubes for centrifuging and inserting them into a centrifuge at an angle. The '771, '760, and DE patents in particular, relate to flexible holders for centrifuge test tubes.
It should be noted that the problem which the present invention comes to solve also relates to the removal of test tubes from a centrifuge without the need for individual manipulation of each test tube. With specific reference to U.S. patent application 2010/0031760, this prior art teaches the use of a flexible strip test tube holder that can change its shape and assume a conical shape having an angle corresponding to that of a centrifuge rotor. The flexible strip has an additional rib by which it is wedged into a corresponding recess in the centrifuge. In standard, legacy centrifuges, however, this recess does not exist and therefore in order to use this flexible strip the centrifuge apparatus requires modification, limiting the usefulness of this test tube holder, since it is unsuited for the most common types of centrifuges in use today. In contrast, the present invention is suited for use with most centrifuges that are found in a majority of laboratories. There is no need, as in the previous case, for changes or adaptations in existing legacy systems.
In addition, the flexible strip of the above-mentioned, patent publication, because it is a strip and not a ring, enables simple entry of all the test tubes at one time into corresponding designated cells in a centrifuge. This entry is effected with the assistance of an additional hard strip that is not flexible. The difficulty is that such an arrangement does not allow simultaneous removal of all the test tubes that are aligned in a circle in the centrifuge, as a group. There is no provision for holding the strip in order to pull it out of a centrifuge. Moreover, there is no provision for allowing withdrawal of all the test tubes together in a cyclic manner (upward and inward, as explained hereinafter).
In contrast, the present invention enables vertical and angular movement of all the test tubes (or centrifuge tubes) together in a circular manner. Thus all the test tubes may also be removed at one time and transferred as a group to a rack.
In short, the problem which the present invention addresses is not only the entry of the test tubes into a centrifuge rotor at an angle, a problem which has been solved in many ways, but in their simultaneous removal. The solution to the problem provided by the present invention is unique and comprehensive and applicable to commercial centrifuges available in the vast majority of laboratories and institutions worldwide.
It is therefore, desirable to provide an inexpensive and efficient apparatus, system, and method that will allow the simple entry and removal, respectively, of all the test tubes into and from, a centrifuge simultaneously, without the necessity of handling each test tube individually.
Furthermore, the present invention comes to orient the test tubes into a ready position for simultaneous entry into and removal from the apertures of a centrifuge rotor. This additionally overcomes the problem of individual, time-wasting handling and positioning of the test tubes as is generally done today. After centrifuging, the test tubes can be conveniently and simultaneously lifted out of the centrifuge and returned to a rack for further inspection and processing as needed.
The present invention further involves providing a round test tube rack suitable for holding test tubes for transfer and retrieval from standard centrifuges.